Radio navigator



April 6, 1943. L, A. WARNER 2,315,754

RADIO NAVIGATOR Filed June 19, 1939 3 Sheets-Sheet 1' IIIIIIIF' 56 3 51jHlllll m 59 April '6, 1943. L. A. WARNER RADIO NAVIGATOR 3 SheetsSheet.2

Filed June 19, 1939 -11 ll lllll lllllll llLi 75 5 II II /MI]JJIHI I I HIllllill" l l W April 6, 1943. L, A. WARNER 2,315,754

RADIO NAVIGATOR Filed June 19, 19:59 3 Sheets-Sheet 5 W I 0% 70 g; (Z? I74 75 70 Jazz zxfl, 1%:

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Patented Apr. 6, 1943 STAT S ATE 1 14 Claims.

This invention relates to radio controlled automatic pilots foraircraft, watercraft and like vessels, in general. More particularlythis invention relates to navigating apparatus in which an automaticradio compass and a magnetic or gyroscopic compass are so coupled thatthe radio compass is made to perform functions normally assigned to anavigating agency.

An object of this invention is to provide a navigating apparatusemploying a radio compass and a magnetic or gyroscopic compass coupledthereto, said compasses being arranged so that the course selection forthe mobile craft and the rudder control thereof are two separatefunctions.

Another object of this invention is to provide an automatic pilotapparatus for mobile craft adapted to correct for yaw.

A further object of this invention is to provide an automatic radiocompass with means whereby said compass is adapted to be used as anavigator, for orientation, drift correction and for homing.

Still another object of this invention is to provide an automatic pilotfor mobile craft in which course selecting apparatus is employed but inwhich the automatic pilot does not function until after the course isselected.

Still a further object of this invention is to provide an automaticpilot in which the navigating functions of the automatic radio compassare arrested or cut out during simple yaw of the craft.

Another object of this invention is to provide a navigating apparatusemploying a radio compass in which the crab angle is selectedsimultaneously as the radio compass loop is rotated after the nullreception position of the loop is disturbed by drift of the craft.

Still another object of this invention is to pro vide a navigatingapparatus for mobile craft in which a radio compass is coupled with amagnetic' or gyroscopic compass, said coupling con-- nections of thisapparatus; Fig. 2 is a view of the magnetic compass and illustrates theconnection between this and the gear shaft and Figs. 3, 4 and 5 aredetail views of the gear set.

Referring to the drawing in detail, reference numeral Ill designates aloop antenna connected by wires H and ii! to the input of a radio signalreceiver and amplifier l3. The receiver and amplifier I3 is alsoconnected to a substantially nondirectional antenna i4 and the signalenergy received from both the loop ill and antenna M are mixed incertain desired phase relation to produce directional signal reception.For this purpose the circuit arrangement employed in the apparatus 13may be of the type described in Patent No. 2,144,309 issued 'to C. W.Hicks in which a'directional antenna or loop and a non-directionalantenna are connected to a radio signal receiver and amplifier for thepurpose of obtain ing directional reception. It is of course obviousthat I may employ other circuits than the aforesaid Hicks circuit forproperly phasing the signal currents and potentials derived from theloop antenna and the non-directional antenna since various forms ofthese circuits are Well known in the art as exemplified by my priorPatent No.

2,051,974 and I therefore do not desire to restrict myself to any oneparticular circuit since various circuits may have advantages dependingupon the circumstances surrounding the use thereof. a

The output of the radio receiver and amplifier is connected to thewinding of the polarized relay I5, the radio null indicating instrumentl6 and the relay IT. The instrument I6 is. provided with a pointeractuated by a dArsonval or similar electromagnetic meter movementpolarized to indicate when the craft is bearing to the left or the rightof the radio course. The relay i1 is shown as an auxiliary instrumentalthough it could be incorporated into the relay l5 by pro vidinganother pair of contacts one on each, side of the armature l5substantially the same as the contacts l9 and 20. These two additionalcon tacts would be connected together and to the wire 25 to close thecircuit of. the solenoid 26 the same as when the relay i1 is energized.

When the armature I6 of the polarized relay I5 is deflected toward theContact [9, that is. when the craft. drifts to the left, for example,the loop rotating motor 2|, is energized from the source of currentsupply; such as, the battery 24 through the resistance 22. This motorbeing geared to the loop rotating shaft 23 causes the loop to be rotatedin one direction when onergized through the circuit of relay contact l9and in the other direction when energized through the circuit of relaycontact 29. Thus the loop is rotated to seek the null signal point atwhich the relay I is substantially not energized through the action ofsignal energy. A resistance 22 is connected between the field windingsof the series-compound motor 2| to act as a braking device to reducerotation of the motor armature because of inertia thereof, after themotor is de-energized.

A radio azimuth indicator 2! is also provided to the shaft 23 toindicate the azimuth of the loop antenna which is usually positioned onthe outside of the aircraft or watercraft cabin out of the operators,pilots or navigators view. On aircraft the loop antenna is oftenenclosed in a tear drop shaped housing to decrease wind resistance andthe loop is rotatable inside of this housing out of sight so that it isnecessary to employ a loop azimuth indicator. Furthermore it may appearfrom the drawing that the shaft 23 is a rigid member and it is of courseapparent that flexible shafting similar to the Bowden type may beemployed.

When the clutch operating solenoid 26 is energized from the currentsource 24 through the operation of the relay I! the clutch members 28and 29 are caused to engage through the magnetic action of the solenoidand the shaft 32 is linked to the shaft 23 whereby these shafts arerotated together by the motor 2|. At the same time as the clutch members28 and 29 are brought together the contacts 30 and 3| are interrupted sothat the circuit of the rudder control relay is open at these contactswhile the radio loop and justed. through the operation of the motor 2|.The purpose of this will be more fully brought out in followingparagraphs of this specification.

The winding of the relay 36 is connected to the contact 30 and to thewinding of the polarized relay 33 which in turn is connected to anelectrode 49 of the electrolytic resistance device 35. The device 35 isconstructed in accordance with the disclosure of Patent No. 1,932,329 ofUrfer although it is of course obvious that similar devices employingwiping contact resistance elements instead of electrolytic conductingpaths may be employed if. desired. Another electrode 59' similar toelectrode 49 is provided to the device 35 and is connected to the yawindicator 39 which in turn is connected to the contact 3|. The yawindicator 39 is a meter similar to the radio null indicator i6.

The electrolytic device 35 consists of a container 43 preferably ofinsulating material, supporting contacts 44, 45, 46 and 4'! in anelectrolyte. The electrodes 49 and 50 are supported in the electrolyteon suitable supports. An insulation member 43 is pivotally supported insaid electrolyte and is provided with suitable magnets to adjust theposition of the insulation member 48 with respect to the earths magneticfield so that portions of this insulation member may be the courseselector compass 34, are being adinterposed between certain electrodesof the de vice 35 and the electrical resistance of the current paths ofthe device varied in the course selecting operation.

It will be observed that electrodes 44 and 45- 41 on one side andelectrodes 45, 49 and 46 on the other side with the insulation member 48in the position illustrated. If the insulation mem- 'ber 49 is shiftedso that the path through the electrolyte is increased between theelectrodes 44 and 50 and between electrodes 46 and 49 on the one hand,the path through the electrolyte between electrodes 45 and 49 andelectrodes 41 and 59 is reduced on the other hand so that the currentflows between the electrodes 45 and 49 through the winding of thepolarized relay 33, the relay 36, contacts 30 and 3|, yaw indicator 39and electrodes 41, 50 to the other terminal of the battery 24 tocomplete the circuit. If the insulation member 48 is turned or shiftedin the other direction the current flows in the opposite direction andproduces an opposite indication in the yaw indicator 39. The polarizedrelay 33 may be deflected in either direction so that the armature 4|engages either contact 4 0 or 42 9 depending upon the direction ofcurrent flow through the winding of this relay as determined by thecompass device 35.

The armature 4| of the relay 33 is connected to one terminal of thebattery 24 for the'purpose of energizing the motor 5| through thecontacts 40, 42 When the relay is energized. Both of the contacts 40, 42are connected to the motor 5| so that this motor may be rotated eitherclockwise or counterclockwise depending upon the energization of thepolarized relay 33. The motor 5| is also of the series compound typesimilar to the able means to the wheel 60 mounted on the shaft 59.

The variable resistance device including the resistances 66 and 61 isarranged to be controlled in accordance with the rotation or angularmovement of the shaft 59 by coupling the contact arms 64 and 65, joinedtogether by a piece of insulation material, to the aforesaid shaft. Thecontact arms 64 and 65 are connected to the terminals of one of thewindings 55a of the clutch solenoid 55 and the resistances 86 and 61 areconnected to the terminals of the battery respectively, whereby thesolenoid winding is energized to an extent depending upon the positionsof the contact arms. The other winding 55b of the solenoid 55 isconnected across the brushes of the motor 5|.

Thus the winding 55b is always energized in series with the motor 5| andthe direction of current flow through this winding depends upon which ofthe contacts 49 or 42 of the polarized relay 33 i in circuit. A variableresistance 68 is connected in series with the winding 55b so that theenergization of this winding may be controlled by the operator ifdesired. The lower winding 55a of the clutch is employed for the purposeof knocking down the clutch element 53 to prevent overcontrol of therudder. When this winding is energized the current flowing through itflows in a direction opposite to that in the upper winding 55b. Sincethe winding 55a is energized through the resistances 66-61 which arevaried in accordance with the position of the rudder-shaft 58 thiswinding will be energized in a definite direction and in a definiteamount. When however the arms 84 and 88 are contacting the points of theresistances 68 and 87, re-

spectively connected to the terminals of the battery 24 the winding 55ais being fully energized with very little of the resistances 6B and B1in circuit. As was mentioned above the purpose of the winding 55a is tomagnetically bias the clutch and knock it down to prevent over controlwhen the craft is nearing its on course position and it will be observedthat as the craft is approaching on course position thiswindingapproaches maximum energization so that it is then able toovercome the magnetic effect of the winding 55b. The clutch 54 mustrelease before the craft is on course" because otherwise the craft wouldswing far past its "on course" position and this is accomplished by theWinding 55a.

The gear set 59 which is illustrated in detail in Figs. 3, 4 and 5 isconnected between the clutch plate 29 and the compass course selector 3dto the shafts 32 and 32a. The gear set is provided with a gear shiftlever I0 which has three positions, namely, ahead," homing and astern.When the lever I0 is in its ahead position the apparatus is adapted tobe used in connection with a radio transmitting station located ahead ofthe craft being navigated. When the lever I8 is in its astern positionthe apparatu isa reversing idler gear I5 which in turn drives the gear16 mounted on the course selector shaft 821;

when the gear shift lever 10 is in its astem position shown in Fig. 3.The gear 18 is one-half the diameter of the gear I4 and is thereforerotated twice the number of revolutions as the gear I6 and in the samedirection inasmuch as the reversing gear I5 is interposed between thegears I4 and I6. Thus in the astern" position the shaft 32a is rotatedin opposite direction to the shaft 32 and at twice the angular velocity.

The lever I0 is pivotally mounted on the housing of the gear set by thepivot Illa. On the inl side of the gear housing is provided a slidablegear shifting member 11 which is pivoted to the lever ID at I8 and issupported by the bar I9 passing through sliding collars 80 of the memberI1. Three sliding gear forks 8i, 82 and 83 are employed by the member'II for shifting the positions of the gears I6. 84 and 85 mounted on thesplined shaft 3211. It will be observed that when the lever I0 is in theastern position that the gear I5 meshes with the gear I5 as explainedabove and that gears 84 and 85 are idling.

When the lever 10 is shifted to the homing" position shown in Fig. 4 thegear 16 is caused to disengage the idler gear I5 and the gear 84 is slidinto mesh with the gear 86. The gears 84' and 86 bear a one to one ratioto each other and consequently when these gears mesh the course selectorshaft and the shaft 32 rotate in the same direction and at the sameangular velocity. When the lever Ill is shifted to its "ahead" positionas shown in Fig. 5 the gears 84 and 86 are caused to disengage and thegears I5 and I6 are left disengaged while the gears 88 and in an broughtinto mesh. These gears and 8? heal a one to two ratio, that is, the gear85 is onehali the diameter of the gear 87. and consequentl rotate theshaft 820; a of the course selecto: through twice the angle throughwhich the shaf 32 is rotated. Inthiscase the shafts 32 and 321 rotate inthe same direction.

In Fig. 2 I have shown a detail view of th mechanical connection 35abetween the electro lytic resistance compass device 35 and the shaf 32a.Both of these shafts 32a and 35a are ro tatable by the manual crank 34athrough th bevel gears 36b and 340 so that the compass de vice 35 may beset on a certain course indicate by the compass card 35d which isrotated simul taneously therewith by the crank 34a durinl manualadjustment or by the shaft 32a durim adjustment by radio.

- The operation of the apparatus of my inven 'tion may be bestunderstood when it is consid ered from the standpoint of each of itssevera functions. The radio compass as employed ll accordance with thisinvention indicates drift no only electrically but also as an azimuthreading It further is made to select through the previous ly describedgear coupling, crab angle course that correct the drifting tendency andfor tha purpose can use radio transmitting stations botl ahead andastern. Another navigational fea ture isthat the radio compass initiallyorient the aircraft on to its course towards its destina tion and, usingstations ahead it may be use automatically to select a homing path.Further more the apparatus of my invention is also useft in blindlanding systems as will be apparent fror this specification.

To correct for drift the loop rotation of th automatic radio compass isutilized to mechani cally rotate a course selector 34-45 throughclutching and gear arrangement including th clutch 2829 and gear set 69at a ratio of mor than one to one, that is, with the gear lever i seteither in its ahead or astern" position The aircraft or other vesselbeing navigated thereby headed into the wind at a crab angl whichcounteracts drifting. This is accomplishe as follows: Drift along thelateral axis of th craft occasioned by winds will destroy the equlibrium in the null seeking loop in. The voltage then induced into theloop are combined wit those induced into the sense antenna Id in radioreceiver I3 which through phasing an amplifying arrangements operates toproduce a indication in a zero center meter I6 and to actl ate thepolarized relay I5. The loop control I! -lay I5 then functions to supplycurrent in ti proper direction to the loop rotator compoun wound motor2| which rotates the loop in a d rection to restore it to the nullposition with l'( spect to the radio transmitting station. Whe the nullposition is regained the armature of ti relay I5 is restored to normalposition and cm rent no longer flows to the loop rotator mot 2 I. Theresistance 22 connected across the moth armature through the fieldwindings functions 2 ,an electrodynamic brake to bring the motor toquick stop. During the aforesaid null seekir. period the loop azimuthindicator-21 was a]: rotated and indicates the direction and angle 1loop swing. While the radio compass functions as described above thefollowing drift correctir operation took place. Simultaneously with tioperation of the relay I5 through the operatic of the radio compass, theclutch relay ll ope to supply current to the clutch solenoid 26 h closedthe clutch plates 28-29 and couthe loop shaft 23 to the course selectorshaft The cone clutching'plate 29 is so constructed it turns with thecourse selector shaft 32 a it is simultaneously movable longitudinallyhe splinecl end thereof. This transmits the rotating torque on to thegear set 69 wherein gearing arrangement integrates this rotation rat thecourse selector shaft 32a is rotated ratio of more than one to one. Itis imint to note that during this process of course tion into the windthe rudder control mechn is opened at the clutch contacts 3U3l preventsswinging of the craft itself while crab angle course is being selected.When oop regains its null position, the course se- Jn has beenaccomplished, and the relay 1'! l-energized so that the clutch winding26 is de-energized and the clutch armature 29 s thereby closing thecontacts 303I which the rudder control circuits that function to g thecraft about to its new crab angle head- Briefiy then the automatic radiocompass selects the drift correcting course and at the )letion of thattask it allows the magnetic 38.55 control element to swing the craftonto :ourse. Thus the course selection and the er control are twoseparate functions or opons. The separation of these two functionsitally essential for practical navigational )IlS as will become apparentfrom the wing. iring the time that the craft is being swung nd onto itsnew crab angle course the loop g a physical part of the craft will turnwith id will bring into play the null restoring acof the automatic radiocompass system and rotate the loop in a direction opposite to that hichthe plane itself is turning. It is evident the loop rotating action torestore its alignt on hearing must not at this time affect the seselector in any way. The clutch cut ofi re- 36 functions to separate theloop rotating b from the course selecting shaft during this swing of theloop. It operates just as soon as :ourse selection function has beencompletnd the clutch has been released. The clos- )f the contacts 30-3!closes the circuit for relay 36 along with the relay 33. This opensbreak contact 31 of the relay 36 and opens circuit to the clutch winding26, keeping it L until the craft has reached its new "on se heading whenthe relay 36 releases at the of a course correcting cycle. beencountered the same cycle of events will at themselves. ius far driftor movement along the lateral of the craft have been considered and noweffects of yaw or simple rotation about the ;s vertical axis occasionedby local turbulence be considered. Yaw will likewise affect the Jequilibrium in the loop and will actuate the matic radio compass. Theloop will rotate ltly during yaw but this cannot be allowed to at, thecourse selector. The correction for is never more than a one to oneratio of turn.

Should more ating relay 36 effectively separates the loop rotator shaft23 from the course selector shaft 32 at the clutch 28--29 by opening thecircuit at 31 to the clutch winding 28 during a yaw or turningcondition. A turn around the vertical axis disturbs the equilibrium inthe directive element in the compass resistance 35 and current flowsthrough the rudder control relay 33, the relay 36 and the yaw indicatorsimultaneously. The relay 36 quickly acts to open the clutch circuit atits break contact and prevents the clutch from operating during simpleyaw.

The directive element in the compass appa ratus 35 is fundamentally partof a Wheatstone bridge circuit with electrolytic resistances in thebranches. Current is fed to the bridge through four points substantiallyequally spaced around the shell 43 thereof. Yaw indicator and controlcircuits are connected to electrodes 43- and 56 supported in theelectrolyte of this compass apparatus. Yawing disturbs the bridgecircuit balance and current flows in the control and indicating circuitsin a direction dependent on the direction of turning. This operates therelay 33 in such manne that the rudder control motor 5| functions tobring the craft back to its cortherefore very evident that a more thanone rect course thereby restoring balance in the bridge circuit. Arotation of the shell 48 of the compass apparatus 35 manually by thecrank 34a or by the loop rotating torque in effect changes the coursesince it also disturbs the bridge circuit balance and requires rotationof the craft in a proper direction to restore the balance.

The gear set 69 is an essential part of this system since it enables anintegration of the loop rotating action into four distinct navigationalfunctions, namely, homing, orientation, automatic drift correction usingradio station ahead of the craft and automatic drift correction usingradio station astern. For homing, rotation of the clutch shaft 32 istransmitted to the course selector shaft 32a through the geararrangement 69 at a ratio of one .to one and in the same direction. Fororientation the same gear arrangement 69 is used at the outset of aflight to automatically select the initial course towards thedestination point. For automatic drift correction using a radio stationahead the rotation of the clutch shaft 32 is transmitted to the courseselector shaft 32a through the gear arrangement 69 at a ratio of morethan one to one and in the same direction. This in effect picks a courseinto the wind to counteract the drifting tendency. For automatic driftcorrection using a radio station astern the rotation of the clutch shaft32a through the gear arrangement 69 at a ratio of more than one to onepreferably two to one in an opposite direction. A course into the windis likewise selected and drift corrected. Thus if a wind conditionfrom'the left producing drift to the right is assumed, with the gearshift lever 10 in the ahead position, the loop rotation to the left toregain the null position will be transmitted through the gear set 69 tothe upper sliding gear which is half the diameter of its meshing gear 81and will rotate the course selector shaft 32a through substantiallytwice the angle and in the same direction as the clutch shaft. Under thesame condition of drift with the gear shift lever 10 in the "asternposition the loop rotation th s time to the right will be transmittedthrough the gear set to the lower sliding gear I6 which is half thediameter of its driving gear 14 and reverses the direction of rotationwithout affecting the gear ratio. The use of astern bearings is uniqueduring periods of poor radio 7 the automatic radio compass is beingutilized for in that it. offers drift corrected navigation away is noradio station.

from a station towards a point at which there The clutch switch 38manually breaks the link position finding and bearing taking purposes.This switch is. likewise used to open the clutch circuit when shiftinggears on the gear set 69 and prevents a loop rotatin'gaction fromdamaging gears while changeover'is taking place.

I have described the various features of my invention indetail, however,I do not desire, to limit this invention to theexact details setforth inthe foregoing specification except insofar as such details may bedefined in the claims.

What I claim has follows:

v 1. A radio navigational control, comprising a rotatable directionalantenna system adapted to be carried by'avehicle, means forcontrollingthe rotation of said antenna system for maintaining saidsystem pointing ina predetermined direction with respect to a selectedradio transmitting station, a crab angle indicator, and means forrotating said crab angle indicator in a direction opposite that of theantenna rotation and through an angle substantially greater thanthemeans, for utilizing the antenna rotating action to revolve saidcourse selecting. device, automatic means for steering the craft inaccordance with the position-of the saidlcourse selector device and itsassociated magnetic orvgyroscopic directiveelement... a clutchinterposed between said antenna shaft and said course selector shaft forthe purpose-of connecting the two shaftsmeans 1 for rendering the clutchin an operative condition a course into the wind.

angle through which the antenna is rotated, for-v indicating the crabangle of; said vehicle, when using a radio transmitting station asternof the craft for navigational-reference:

i 2. A radio controlled automatic pilot, comprising a. rotatabledirectional antenna system, means by which said antenna system may bemaintained oriented with respect to a point used for'navigationalreference, a course changingdevice, means for coupling the rotary actionincldent to such antenna orientation to said course changing device,means in said last mentioned means for rotating said course changingdevice in a direction opposite that of the antenna at a ratio ofsubstantially more than one to one when using a station from behind thecraft for navigational reference, means whereby saidchange of positionof said course changing device controls the steering of the craftautomatically, to navigate the craft along a crab angle course, and toeffect a straight track with respect to the ground.

3. A radio navigational control system, comprising: a rotatable antennasystem, a rotatable shaft for said antenna ystem, automatic means forrotating said antenna system to point in a predetermined direction,automatic steering means including a course selector, a rotatable shaftfor said selector, means for utilizing this rotary action to revolvesaid course selector shaft, a clutch interposed between the antennashaft and the course selector shaft, said clutch being maintained in aninoperative condition lowassociated electrical circuits in saidautomatic teering means to prevent rotation of said course selectorthrough said course selector shaft by said antenna shaft during periodthat yawing is taking place, delegating the function of yaw correctionto the automatic steering means controlled by the magnetic 'orgyroscopic directive element.

4. A radio navigational control system comprising: a rotatable antennasystem, a rotatable shaft for said antenna system, automatic means forrotating said antenna system to point in a predetermined direction, acourse selecting device, a shaft for adjusting said course selectingdevice,

when a new .course is being selected, and break contact means connectedto said clutch for dis- .ablingsaidautomatic steering means andpreventing said steering-means from acting to change the heading Ofthflcraft being steered during the period that a new course is beingselected, thereby assuring a antenna system and the course selector toachieve 5. A radio navigational control system, comprising: a rotatableantenna system, a rotatable shaft for said antenna system, means'forrotating said antenna system to pointin a predetermined direction,a-radio receiver connected to said antenna, a course selecting device, ashaft for adjusting said selecting device, means for utilizing theantenna rotatingaction to revolve said course selecting device,"automatic means for steering the crafti'n. accordance with the positionof said course selector device, including a 'rudder motor and rudderturning means, electrica'l means for preventing overcontrol of therudder of the craft by said steering means, com-.;

prising, a clutchinterposed between said rudder motor and said rudderturning means, said clutch alternately connecting and disconnecting saidrudder motor shaft and the rudder turnin shaft, and comprised of two ild One Winding energized simultaneously with and in the same direction asthe motor armature, the other winding energized by a variable resistancedevice actuated by the rudder shaft in such a mannor that currentthrough it is in an opposite direction, means functioning to release the:clutch when the rudder moves off center by a definite amount, allowingthe rudder to return to the midship position before the on course"position of the craft is reached.

6. A radio navigational control system, comprising: a rotatable antennasystem, means for rotating said antenna system to point in apredetermined direction, a course selecting device, a clutch and gear,means for utilizing the antenna rotating action to revolve said coursese-' lecting device through said clutch and gear, automatic means forsteering the craft in accordance with the position of said courseselector, 2.

motor for operating the rudder of the craft, automatic means forpreventing overcontrol of the rudder action, comprising a clutchoperated by a pair of windings, one winding in shunt to the said ruddermotor armature circuit, semi-circular re sistances. a pair of contactorsmovea'ble thereover, a shaft connected to the crafts rudder for movingsaid contactors, the other winding connected to said moveable contactorarms, the energization of the two windings being controlled to'release athe rudder at the-proper time without affecting theoperation of themotor control means, the yaw indicator, ,or associated electricaldevices.

7. A radio controlled automatic pilot, comprising: course changingmeans, rotative radio directional means, means responsive to therotation of said rotative radio directional means for rotating saidcourse changing means, automatic steering means responsive to theposition of said full swing of both the towards a predetermined hiclefor automatic drift correcting navigation,

means responsive to said magnetic or gyroscopic compass for renderinginoperative said course changing means during a condition of yaw, and

automatic means for maintaining directional stability around thevertical axis by means responsive to magnetic or gyroscopic directivemeans.

8. A radio controlled automatic pilot, comprising: course changingmeans, rotative radio directional means, means responsive to therotation of said rotative radio directional means for vro--- tating saidcourse selecting means, automatic steering means responsive tog theposition of said course selecting means to steer, the craft onto and tomaintain the course selected by said course selector means, saidautomatic steering means including a magnetic or gyroscopic compass,means for rotating said course selector in a direction opposite that ofthe rotative radio directional means at a ratio of. more than one to onewhen using a radio transmitting station at a point astem of the craftfor automatic drift correcting navigation, means responsive to saidmagnetic or gyroscopic compass for preventing the functioning of saidcou'rse selector during a condition of yaw, and automatic meansresponsive to magnetic or gyroscopic directive means for maintainingstability around the vertical axis.

9. A system for steering moving craft along a predetermined,substantially straight track under conditions of yaw and drift,comprising: a radio direction finder having a rotatable loop and meansconnected to the radio direction finder for rotating said loop withrespect to a selected radio transmitter, a. compass course selector, agear arrangement mechanically connected between said rotatable 100p andsaid compass course selector for setting said course selector inaccordance with change in setting of said rotatable loop to compensatefor effects of drift of the craft, said compass course selector .beingsensitive to yawing of the craft, and means connected to said compasscourse selector for preventing resetting of said compass course selectorduring yawing of the craft.

10. A radio navigator, comprising: a rotatable Q directional antennahaving a rotatable shaft,

means for maintaining said antenna oriented point, acourse indicatingand selecting device having a'rotatable shaft, means for imparting theangular movement of said antenna shaft to said course indicating andselecting device shaft, clutching means for alternatingly engaging anddisengaging said two shafts, means for energizing and operating saidclutch simultaneously with said antenna rotation during drift andrapidly acting electrical means for preventing the operation of saidclutch during yaw and while the craft being navigated is being orientedon to its course.

11. A course navigational system for yaw and drift correction,comprising: means for detecting and correcting yawinz, cluding means toeffect course change corrections at a ratio of one to one with respectto the yaw angle, means for detecting and correcting drifting, includingmeans to effect course change corrections at a ratio of more than one toone with respect to the drift angle, and means to differentiate betweenthe yaw and drift corrective actions, so that the said one to one ratiocorrection will be applied for yaw, and the said more than one point,including mechanical rotational means to one ratio corrections will beapplied for drift 12. A course navigational system for drift correction,comprising: means for detecting drifting, means to effect course changecorrections at ratios of more than one to one with respect 'to the driftangle, when points ahead of the craft are used for navigationalreference, means to effect course change corrections, in a reverseddirection, at ratios of more than one to one with respect to the .driftangle, when points behind the craft are used for navigational reference,course change controller means for controlling the directions and ratiosof the said course changes, and means for indicating the position ofsaid course change controller means.

13. The combination in a system for homing and drift correctingnavigation towards a point ahead of the craft, of means for detectingdrifting, means to effect course changes at ratios of one to one withrespect to the drift angle, for homing navigation, means to effectcourse changes at ratios of more than one to one with respect to the'drift angle, for drift correcting navigation, means for controlling theratios of the said course changes, and mean for indicating the positionof the said course change controller means.

14. The combination in a course navigational system, of means toindicate azimuth towards a point of navigational reference, automaticmeans to set the initial course towards the said to efiectcourse changesettings at a ratio of one to one with respect to the angle of azimuthchange, means for controlling the ratio of said course change, and meansfor indicating the position of said course change controller means.LOUIS ALLEN WARNER.

